Study On The Evaluation Of Human Thermal Comfort In Non-uniform Thermal Environment Of Radiant Temperature And Air Temperature

The non-uniform thermal environment formed by the difference between the inner surface temperature and air temperature was one of the common thermal environment characteristics in radiant panel heating,refrigeration,passive solar house and other buildings.The difference between surface temperature and air temperature and the non-uniformity between surface temperatures have an effect on the heat dissipation ratio of various forms of human body,resulting in the change of human thermal comfort.Although the operative temperature could reflect the comprehensive effect of the radiant temperature and air temperature,but it was difficult to characterize the thermal comfort characteristics of the human body in such non-uniform thermal environment when there was a big difference between the two.And existing research on the comfort problem of non-uniform thermal environment mainly focused on the local air distribution,vertical temperature difference and asymmetric radiation.However,there was less research on the non-uniform thermal environment of the differential combination of radiant temperature and air temperature,which hindered the energy-saving design and personalized operation adjustment of the HVAC system to a certain extent.Based on the difference between the radiant temperature and air temperature and the non-uniformity of the internal surface temperature.The difference between radiant temperature and air temperature was taken as the characteristic parameter of non-uniformity,the effects of two types of typical non-uniform thermal environments on human thermal comfort were studied through the artificial climate chamber experiment in this study,including:（1）All the interior surface temperatures were equal,but the surface temperature and air temperature were not equal,namely uniform radiant thermal environment（ANUE）;（2）The surface temperature of only one inner surface was not equal to the air temperature,that is,a single surface non-uniform radiant thermal environment（SNUE）.In addition,the effect of air velocity on human thermal comfort in a hot non-uniform thermal environment was investigated.In this study,a batch of healthy subjects were selected and 22 experimental conditions were set up according to different levels between surface temperature and air temperature（0℃,2℃,5℃and 10℃）for the above two types of typical non-uniform thermal environment to conduct an artificial climate room experiment.The thermal response characteristics of the human body in a non-uniform thermal environment were revealed by testing objective physiological parameters such as human skin temperature,heart rate,blood pressure,and investigating and collecting subjective thermal responses such as human thermal sensation,thermal comfort,and acceptability.Based on correlation analysis and bayesian information criterion（BIC）,the human thermal comfort models（TDP models）suitable for two types of non-uniform thermal environment was established,and the combination relationship between air temperature and radiant temperature satisfying human thermal comfort was obtained.On this basis,by analyzing the influence law of air velocity on human thermal response in the non-uniform thermal environment with different combination of air temperature and radiant temperature,the improvement degree of air velocity to human thermal comfort level in hot non-uniform thermal environment was mastered.The main results of this study were as follows:（1）There was a separation between human thermal sensation and thermal comfort in non-uniform environment.PPD=10%was taken as the thermal comfort boundary value.In ANUE environment,the lower offset of the operating temperature(t_op)for thermal neutrality and thermal comfort was 1.5℃and the upper offset was 0.4℃.In SNUE thermal environment,when the human body was in a thermally neutral state,the deviationof the dissatisfaction（?PPD）rate reached a maximum of 22%.（2）The thermal comfort models of human in ANUE and SNUE environment（TDP models）was established,and the different combination interval of radiation temperature and air temperature to satisfy the different thermal comfort of human and the multi-parameter evaluation index were obtained.For ANUE environment,TDP was less than25%when air temperature ranged from 23.6℃to 28.7℃,and surface temperature was10℃higher than air temperature.For SNUE environment,TDP was less than 25%when air temperature ranged from 23.6℃to 27.8℃,and surface temperature was 6.5℃higher than air temperature.（3）In the hot non-uniform thermal environment,the increase of air velocity improved the thermal comfort of human.In ANUE environment,the dissatisfaction percent with the thermal environment at v_a=1.2m/s was 25%lower than that at v_a=0.6m/s.Compared with v_a=0.1m/s,dissatisfaction percent decreased by 56%.In the SNUE environment,the dissatisfaction percent with the thermal environment at v_a=1.2m/s decreased by 2%～18%compared with that at v_a=0.6m/s.Compared with v_a=0.1m/s,the reduction was 11%～35%.This study clarified the characteristics of human thermal comfort in two types of typical non-uniform thermal environments with differential combination of air temperature and radiant temperature.Based on the traditional single index of indoor thermal environment evaluation such as operating temperature,a multi-parameter evaluation index system for indoor air temperature,radiant temperature,and air velocity was established,it also improved the evaluation method of non-uniform thermal environment in buildings.